Pump system for zonal isolation testing

ABSTRACT

A pump system for testing an isolated zone in a borehole includes a testing pump and a testing device. The testing pump may be configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole. The testing pump may be powered by a power fluid, where the power fluid may be delivered from a power fluid source. The power fluid source may be located at a location remote from the testing pump. The testing device may be configured to monitor the formation fluid flow. The testing device may further be configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

PRIORITY CLAIM

This application claims priority to Provisional U.S. Patent Application No. 60/802,926 filed May 24, 2006, entitled “A PUMP SYSTEM FOR A ZONAL ISOLATION TESTING TOOL,” the entire disclosure of which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

This invention relates generally to testing earth formations in wellbores. More specifically the invention relates to testing earth formations in isolated zone testing in wellbores.

During or after a gas and/or oil wellbore is drilled, testing may need to be done to determine characteristics of the earth formations through which the wellbore penetrates. These characteristics may assist in determining the potential productivity of the wellbore, or if further treatment after drilling will be necessary to increase productivity of the wellbore (also referred to herein as a borehole).

A typical way of testing a borehole may require the drilling equipment to be removed from the borehole, after which testing equipment may be run down the borehole. Boreholes may be very deep, depending on the location of the drilling, and therefore many thousands of feet of drilling equipment may have to be removed from the borehole, before many thousands of feet of testing equipment is inserted back into the borehole. Therefore, testing a borehole may be very time consuming process.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment of the present invention, a pump system for testing an isolated zone in a borehole is provided. The pump system may include a testing pump and a testing device. The testing pump may be configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole. The testing pump may be powered by a power fluid, where the power fluid may be delivered from a power fluid source, which may possibly be located at a location remote from the testing pump. The testing device may be configured to monitor the formation fluid flow. The testing device may also be configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

In another embodiment, a method for testing an isolated zone in a borehole is provided. The method may include isolating a zone within the borehole, and delivering a power fluid from a power fluid source to a testing pump, where the power fluid source may be located at a location remote from the testing pump. The method may also include powering the testing pump with the power fluid, and creating a formation fluid flow, with the testing pump, from the isolated zone in the borehole. The method may further include monitoring the formation fluid flow with a testing device, and determining characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

In yet another embodiment, a pump system for testing a zone in a borehole is provided. The system may include a first means, a second means, a third means, and a fourth means. The first means may be for isolating the zone in the borehole. The second means may be for assisting, at least in part, in creating a formation fluid flow from the isolated zone in the borehole. The third means may be for powering the first means from a surface location. The fourth means may be for monitoring the formation fluid flow.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in conjunction with the appended figures:

FIG. 1 is an elevation view of a bottomhole assembly just after completion of a borehole drilling;

FIG. 2 is an elevation view of the bottomhole assembly from FIG. 1, after the bottomhole assembly has been tripped to a higher depth, and packers have been set on either side of a first formation;

FIG. 3 is an elevation view of the bottomhole assembly from FIG. 2, after the bottomhole assembly has been tripped to another higher depth, and packers have been set on either side of a second formation;

FIG. 4 is schematic elevation view of a first pump system according to the invention for testing an isolated zone of a borehole using a jet pump;

FIG. 5 is schematic elevation view of a second pump system according to the invention for testing an isolated zone of a borehole using a reverse flow jet pump; and

FIG. 6 is a block diagram of a method of the invention for testing an isolated zone of a borehole.

In the appended figures, similar components and/or features may have the same numerical reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components and/or features. If only the first numerical reference label is used in the specification, the description is applicable to any one of the similar components and/or features having the same first numerical reference label irrespective of the letter suffix.

DETAILED DESCRIPTION OF THE INVENTION

The ensuing description provides exemplary embodiments only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiments will provide those skilled in the art with an enabling description for implementing one or more exemplary embodiments. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the appended claims.

Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, systems, structures, and other components may be shown as components in block diagram form in order not to obscure the embodiments in unnecessary detail. In other instances, well-known processes, techniques, and other methods may be shown without unnecessary detail in order to avoid obscuring the embodiments.

Also, it is noted that individual embodiments may be described as a process which is depicted as a flowchart, a flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. Furthermore, any one or more operations may not occur in some embodiments. A process is terminated when its operations are completed, but could have additional steps not included in a figure. A process may correspond to a method, a procedure, etc.

In one embodiment, a pump system for testing an isolated zone in a borehole is provided. The pump system may be used as a formation testing while tripping tool, and may in some embodiments be operated without a wireline or other cable. The areas tested by the pump system may include earth formations, earth formation zones, reservoirs, and/or reservoir zones isolated from other areas through which the wellbore penetrates. In some embodiments, the area tested may be different layers of a particular reservoir.

In some embodiments, the pump system may be deployed in an uncased borehole. In other embodiments, the pump system may be deployed in a partially cased well, possibly having perforations in some portions of the casing. In yet other embodiments, the pump system may be deployed in a fully cased well, which has been perforated in some portions.

The zone within the borehole may be isolated by providing at least one packer in an annulus of the borehole. Merely by way of example, to isolate a zone near the bottom of the borehole, one packer may be deployed, while to two packers may be deployed to isolate a zone near the bottom or elsewhere in the borehole.

In an exemplary embodiment, the pump system, or some portion thereof, may be located within a bottomhole assembly. In other embodiments, the pump system, or some portion thereof, may be located within another borehole tool assembly. In yet other embodiments, the pump system may be an independent tool. Therefore, in each of these or other embodiments, the pump system may be coupled with a wireline, mechanical arm, cable, piping, drill pipe, coiled tubing, or by some combination of means. In some embodiments, where packers are used to isolate a zone, the packers may be part of the bottomhole assembly.

The pump system may include a testing pump. The testing pump may be a jet pump, a turbine driven pump, or any other pump which is powered by fluid power. In some of these embodiments, the testing pump may have no moving parts.

The power fluid to power the testing pump may be provided from a location remote from the testing pump. In some embodiments, the location remote from the testing pump may be a surface location. In some embodiments, one or more drilling mud pumps, otherwise possibly used to drill the borehole, may also be used, at least partially, as the power fluid source. In other embodiments, one or more fracturing pumps may also, be used, at least partially, as the power fluid source. The power fluid may include a test fluid, and may also be used to drive a logging while drilling system and/or provide telemetry to drill operators during the drilling process.

In some embodiments, the power fluid may be provided to the testing pump via a power fluid conduit. In an exemplary embodiment, the power fluid conduit may be piping, drill pipe, coiled tubing, or by some combination of means. In these embodiments, at least a portion of the fluid conduit may also be used to deliver drilling fluid to the bottomhole assembly (and possibly specifically the drill head therein), as well as mechanically turn the bottomhole assembly. In yet other embodiments, an annulus of the borehole, the annulus possibly being the area around the bottomhole assembly, the drill pipe, and/or other non-occupied areas of the borehole may also be used as the power fluid conduit.

The pump system may also include a testing device. The testing pump may be configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole by providing draw down at the isolated zone. The formation may have some unassisted fluid flow as well. For the purposes of this specification, the formation fluid flow may refer to any fluid flow from any earth formation, reservoir, etc., or any portion thereof. The testing device may be configured to monitor any portion or more of the formation fluid flows, possibly created or assisted by the testing pump. In some embodiments, the testing pump may draw the formation fluid to and/or through the testing device.

The testing device may be configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow. Characteristics of the isolated zone may include flow measurements, pressure measurements, and/or physical composition measurements. Through the use of embodiments of the invention, high vertical resolution of the characteristics of earth formations may be determined. Furthermore, in some embodiments, instead of using wireline electrical power including using related additional equipment, readily available pumping systems, such as drilling mud pumps and fracturing pumps, may be used to provide sufficient fluid power to power the testing pump. The electrical power systems would require electrical power to be provided in a sufficient amount to overcome hydrostatic pressure head above the testing pump, while fluid power equipment, such as drilling mud pumps and fracturing pumps will be available and already of the power required to overcome the hydrostatic pressure head in the borehole.

Some characteristics may also be further determined by the above measured characteristics or other measured characteristics, including, but not limited to, skin factors, formation characteristics, and/or boundary characteristics. These or other characteristics may also be determined at least in part on operating characteristics of the pump or of the power fluid source (possibly a pump) driving the testing pump, or of the testing pump itself. These operating characteristics may include, merely by way of example, pressure, flow rate, etc.

In some embodiments, the formation fluid and/or the power fluid may be ejected from the testing pump and/or the testing device and into the borehole annulus. In other embodiments, the formation fluid and/or the power fluid may be ejected from the testing pump and/or the testing device and into the drill pipe or other conduit, such as a testing conduit, or possibly a conduit otherwise used to deliver drilling fluid during drilling operations. The formation fluid and/or the power fluid may then continue to a surface location and may be analyzed to determined additional characteristics of the formations surrounding the borehole.

Physical dimensions and operating parameters of the testing pump may be varied to produce different flow rates at different draw down pressures at the formation. In some embodiments, the power fluid flow rate may be adjusted to change the draw down pressure and also the formation flow rate. Also, the type of fluid used for the power fluid can also affect the flow rates and draw down pressures. In some embodiments then, the physical dimensions of the testing pump may be fixed, while power fluid flow rates are changed to vary performance of the testing pump. This may allow performance of the testing pump to be changed as necessary at the surface, possibly dependent on the productivity index of the formation being drawn, while the testing pump is in the borehole, and possibly not modifiable without time consuming tripping from the borehole.

In some embodiments, the testing pump may include a jet pump with a throat and a nozzle. The power fluid may enter the nozzle and drive formation fluid to entrain with the power fluid and pass through the throat. In some embodiments, the nozzle/throat area ratio may be about 0.4 to 0.6, and in an exemplary embodiment may be about 0.54, possibly to minimize power fluid pressure drop through the pump. In some embodiments, the throat diameter may be between about 5 to 7 millimeters, and in exemplary embodiments, between about 5 to 6 millimeters. Some embodiments of the pump system may include debris protection systems to protect these small pathways. These protection systems may include screens, deviated pathways, membranes, etc. Some of these embodiments may allow the testing pump to operate over a wide range of power fluid flow rates with minimal change in draw down pressure.

In some embodiments, particularly those which incorporate the pump system and a telemetry system in a combined tool, a minimum flow may be required to be sent to the tool to maintain telemetry or other operations. In these or other embodiments, a spill valve may allow for a particular amount of power fluid flow to bypass the testing pump, thereby allowing any power fluid flows sent above this minimum to be the amount the testing pump will “see” in operation. If a spill valve or other apparatus to perform the same function is not incorporated in such embodiments, the testing pump may possibly have to operate at least under the minimum power fluid flow required for telemetry or other operations.

In another embodiment, a method for testing an isolated zone in a borehole is provided. The method may include isolating a zone within the borehole, and delivering a power fluid from a power fluid source to a testing pump, where the power fluid source may be located at a location remote from the testing pump. The method may also include powering the testing pump with the power fluid, and creating a formation fluid flow, with the testing pump, from the isolated zone in the borehole. The method may further include monitoring the formation fluid flow with a testing device, and determining characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.

Turning now to FIG. 1, an elevation view 100 of a bottomhole assembly 110 just after completion of a borehole drilling 120 is shown. Note that the figure is not to scale, and is for schematic explanatory purposes.

Bottomhole assembly 110 may include couplings to a drill pipe 130, a body 140, drill collars (within body 140, not shown), a mud motor (within body 140, not shown), and a drill head 150 powered by the mud motor. Bottomhole assembly 110 may also include a pump system for testing an isolated zone of borehole 120 (within body 140, not shown). In this example, the power/drilling fluid for the mud motor may be transmitted from surface pumps, through multiple sections of drill pipe 160, which may be coupled together with coupling pieces 170. In other embodiments, different mechanical systems may be employed to turn bottomhole assembly 110 and deliver power/drilling fluid thereto. Draw down holes 180 in bottomhole assembly 110 may allow fluid from borehole 120 to enter bottomhole assembly.

In this example, borehole 120 passes through various earthen formations 190 including a first formation 190B of interest, and a second formation 190D of interest. In some embodiments, none, some, or all of borehole 120 may be cased during and/or after drilling. The casing may thereafter be perforated near formations of interest. After drilling has been completed in this embodiment without casing, the bottomhole assembly 110 may be tripped from the borehole 120.

FIG. 2 shows an elevation view 200 of the bottomhole assembly from FIG. 1, after the bottomhole assembly has been tripped to a higher depth, and packers 210 have been set on either side of the first formation 190B of interest. In the position shown, formation fluid from first formation 190B of interest may be allowed to flow to draw down holes 180. FIG. 3 shows an elevation view 300 of the bottomhole assembly from FIG. 2, after the bottomhole assembly has been tripped to another higher depth, and packers have been set on either side of the second formation 190D of interest. In the position shown, formation fluid from second formation 190D of interest may be allowed to flow to draw down holes 180. At each of these depths, the pump system within bottomhole assembly 110 may be used to test the zone of the borehole in communication with the respective formation 190 of interest.

FIG. 4 shows a schematic elevation view of a first pump system 400 according to the invention for testing an isolated zone 410 of a borehole 120 using a jet pump 420. In this embodiment, power fluid may be delivered via drill pipe to bottomhole assembly 110, and plumbed to connection 430. Note that FIG. 4 is a non-scaled, schematic view, intended to show operation of first pump system 400. Of the cross sectional area of bottomhole assembly 110, only a portion may be occupied by first pump system 400, allowing power/drilling fluid to pass-by first pump system 400 and continue to other equipment in bottomhole assembly 110, including, merely by way of example, the mud motor which powers the drill head.

After packers 210 may be positioned to isolate zone 410, formation fluid may be drawn down and enter draw down holes 180 as shown by directional arrows 450. The draw down may be generated by power fluid plumbed to connection 430 from the drill pipe (power/drilling fluid supply). Power fluid may flow as shown by directional arrows 455, through nozzle 460 in jet pump 420. The flow of power fluid through nozzle 460 and out throat 465 may cause the draw down at draw down holes 180. Throat 465 may be coupled to an exhaust port on the bottomhole assembly 110 via connection 440, and thereby discharge into an annulus 470 of borehole 120. Note that in other embodiments, connection 430 may be coupled with annulus 470, and connection 440 may be coupled with the drill pipe, using annulus 470 as the supply conduit for the power fluid, and the drill pipe for the exhaust conduit.

The draw down created by jet pump 420 may cause formation fluid to be drawn through testing device 475 per directional arrow 476. Testing device 475 may measure properties of both the formation fluid and of the formation fluid flow and record such information on storage device 480, which is coupled with testing device. The data stored on storage device 480 may then be retrieved after bottomhole assembly 110 has been tripped to the surface.

After the formation fluid flows through testing device 475, the formation fluid may be drawn to jet pump 420 and discharged with the power fluid as shown by directional arrows 485. In some embodiments, the discharge flow may be further analyzed, possibly at the surface, to determine more characteristics about the formation 490. While the exemplary embodiment shown in FIG. 4 has been explained using certain components, some of the components discussed in this specification, or otherwise, may be exchanged with those shown in FIG. 4 in other embodiments of the invention.

FIG. 5 shows a schematic elevation view of a second pump system 500 according to the invention for testing an isolated zone 510 of a borehole 120 using a reverse flow jet pump 520. In this embodiment, power fluid may be delivered via drill pipe to bottomhole assembly 110, and plumbed to connection 530. Note that FIG. 5 is a non-scaled, schematic view, intended to show operation of first pump system 500. Of the cross sectional area of bottomhole assembly 110, only a portion may be occupied by first pump system 500, allowing power/drilling fluid to pass-by first pump system 500 and continue to other equipment in bottomhole assembly 110, including, merely by way of example, the mud motor which powers the drill head.

After packers 210 may be positioned to isolate zone 510, formation fluid may be drawn down and enter draw down holes 180 as shown by directional arrows 550. The draw down may be generated by power fluid plumbed to the annulus 570 of borehole 120. Power fluid may flow as shown by directional arrows 555, through nozzle 560 in jet pump 520. The flow of power fluid through nozzle 560 and out throat 565 may cause the draw down at draw down holes 180. Throat 565 may be coupled to an exhaust port on the bottomhole assembly 110 via connection 540, and thereby discharge into the drill pipe or other exhaust conduit. Note that in other embodiments, connection 540 may be coupled with annulus 570, and the supply connections may be coupled with the drill pipe or other supply conduit, using annulus 570 as the exhaust conduit, and the drill pipe for the supply conduit.

The draw down created by jet pump 520 may cause formation fluid to be drawn through check valve 573 and testing device 575 per directional arrows 576. Testing device 575 may measure properties of both the formation fluid and of the formation fluid flow and transmit such information on storage device using wireless communication antenna 580, which is coupled with testing device. In some embodiments, testing device 575 may be coupled with a siren or other telemetry device via connection 577 to send informational pulses through mud in borehole 120.

After the formation fluid flows through testing device 575, the formation fluid may be drawn to jet pump 520 and discharged with the power fluid as shown by directional arrows 585. In some embodiments, the discharge flow may be further analyzed, possibly at the surface, to determine more characteristics about the formation 590. While the exemplary embodiment shown in FIG. 5 has been explained using certain components, some of the components discussed in this specification, or otherwise, may be exchanged with those shown in FIG. 4 in other embodiments of the invention.

FIG. 6 shows a block diagram of a method 600 of the invention for testing an isolated zone of a borehole. At block 605, a borehole, or a portion of a borehole is drilled. In some embodiments, the borehole may also be at least partially cased and perforated.

At block 610, bottomhole assembly 110 may be tripped toward the surface. When the draw down holes 190 have reached a formational zone of interest in borehole 120, the formation may be isolated at block 615, possibly using packers 210.

At block 620, a power fluid flow may be created, possibly at the surface. The power fluid flow may be delivered to a testing pump, possibly in bottomhole assembly 110, at block 625. At block 630, a formation fluid flow may at least assist in being created by the testing pump.

At block 635, the formation fluid flow may be monitored by a testing device. At block 640, power fluid flow may be adjusted based at least in part on the monitoring of the formation fluid flow. The power fluid flow may be adjusted to optimize testing pump characteristics for the given operating parameters of any portion or more of the system. Adjustment of the power fluid flow may assist in bringing the draw down of the testing pump, and formation fluid flows to within certain general or specific ideal operating conditions of the testing device.

The possibly modified formation fluid flow may be again monitored with the testing device at block 645. At block 650, characteristics of the formation, or fluids flowing from the formation, may then be determined from the monitoring data.

The invention has now been described in detail for the purposes of clarity and understanding. However, it will be appreciated that certain changes and modifications may be practiced within the scope of the appended claims. 

1. A pump system for testing an isolated zone in a borehole, wherein the pump system comprises: a testing pump, wherein: the testing pump is configured to at least assist in creating a formation fluid flow from the isolated zone in the borehole; and the testing pump is powered by a power fluid, wherein the power fluid is delivered from a power fluid source, and wherein the power fluid source is located at a location remote from the testing pump; and a testing device, wherein: the testing device is configured to monitor the formation fluid flow; and the testing device is further configured to determine characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.
 2. The pump system for testing the isolated zone in the borehole of claim 1, wherein the testing pump comprises no moving parts.
 3. The pump system for testing the isolated zone in the borehole of claim 1, wherein the location is a surface location.
 4. The pump system for testing the isolated zone in the borehole of claim 1, wherein the power fluid source comprises a selection from a group consisting of at least one drilling mud pump and at least one fracturing pump.
 5. The pump system for testing the isolate zone in the borehole of claim 1, wherein the testing pump comprises a turbine, and wherein the turbine is configured to be driven by the power fluid.
 6. The pump system for testing the isolate zone in the borehole of claim 1, wherein the pumps system further comprises a power fluid conduit, and wherein the power fluid being delivered from the power fluid source comprises the power fluid moving through the power fluid conduit.
 7. The pump system for testing the isolate zone in the borehole of claim 6, wherein the power fluid conduit comprises a drill pipe.
 8. The pump system for testing the isolate zone in the borehole of claim 1, wherein the power fluid conduit comprises an annulus of the borehole.
 9. The pump system for testing the isolate zone in the borehole of claim 1, wherein the pump system further comprises a bore hole assembly, and wherein the testing pump is at least partially located within the bore hole assembly.
 10. The pump system for testing the isolate zone in the borehole of claim 1, wherein characteristics of the isolated zone comprise a selection from a group consisting of flow measurements, pressure measurements, and physical composition measurements.
 11. A method for testing an isolated zone in a borehole, wherein the method comprises: isolating a zone within the borehole; delivering a power fluid from a power fluid source to a testing pump, wherein the power fluid source is located at a location remote from the testing pump; powering the testing pump with the power fluid; creating a formation fluid flow, with the testing pump, from the isolated zone in the borehole; monitoring the formation fluid flow with a testing device; and determining characteristics of the isolated zone in the borehole based at least in part on the monitored formation fluid flow.
 12. The method for testing an isolated zone in the borehole of claim 11, wherein the testing pump comprises a jet pump.
 13. The method for testing an isolated zone in the borehole of claim 11, wherein the testing pump is at least partially located within a bore hole assembly, and wherein isolating the zone within the borehole comprises isolating the zone after a first at least partial tripping of the bore hole assembly and a second at least partial tripping of the bore hole assembly.
 14. The method for testing an isolated zone in the borehole of claim 11, wherein the power fluid source is selected from a group consisting of at least one drilling mud pump and at least one fracturing pump.
 15. The method for testing an isolated zone in the borehole of claim 11, wherein isolating a zone within the borehole comprises providing a packer in an annulus of the borehole to isolate the isolated zone in the borehole.
 16. The method for testing an isolated zone in the borehole of claim 11, wherein the method further comprises determining, based at least in part on the characteristics of the isolated zone, a selection from a group consisting of a skin factor, a formation characteristic, and a boundary characteristic.
 17. A pump system for testing a zone in a borehole, wherein the pump system comprises: a first means for isolating the zone in the borehole; a second means for assisting, at least in part, in creating a formation fluid flow from the isolated zone in the borehole; a third means for powering the first means from a surface location; and a fourth means for monitoring the formation fluid flow.
 18. The pump system for testing the zone in the borehole of claim 17, wherein the first means comprises a packer.
 19. The pump system for testing the zone in the borehole of claim 17, wherein the second means comprises a selection from a group consisting of at least one drilling mud pump and at least one fracturing pump.
 20. The pump system for testing the zone in the borehole of claim 17, wherein the third means comprises a jet pump. 